Breathalyzer Timing and DUI Defence

Breathalyzer timing can make or break a DUI case. If your test was taken late, the Crown may not be able to rely on the results. Learn how timing issues can create a strong defence.
DUI Lawyer presenting evidence in a criminal courthouse before a judge.

Breathalyzer Timing and DUI Defence

Many people charged with impaired driving believe that a high breathalyzer reading means there is no defence and that the outcome is already decide.

In this case, that is exactly what the client believed. However, a careful review by our DUI lawyers focused on the timing of the breath demand and the delay before testing. That timeline raised serious issues about whether the Crown could rely on the breathalyzer results, which ultimately led to a successful outcome.

At Charitsis Law, our DUI lawyers review each case carefully, examining timing, procedure, and the details that are often overlooked. This focused approach has consistently uncovered issues that can change the direction of a case and lead to charges being successfully defended.

Where you need to speak to a criminal lawyer, call Charitsis Law at 647-930-0200.

Synopsis of Events

Mr. A was driving home at approximately 8:40 p.m. after spending the evening with friends. He had consumed alcohol earlier but believed he was safe to drive.

At approximately 8:48 p.m., Mr. A was stopped by police for a minor traffic matter. During the interaction, the officer formed a suspicion that Mr. A had alcohol in his body and made a roadside breath demand at approximately 8:52 p.m. Mr. A complied, and the roadside device registered a “fail.”

At that point, Mr. A was arrested and placed in the back of the police cruiser. However, instead of leaving immediately for the station, the officer remained at the roadside. The officer arranged for a tow truck to attend and waited at the scene for approximately 30 minutes before departing.

The officer then transported Mr. A to the police station, which took an additional 25 minutes. Upon arrival, there was a further delay while Mr. A was booked and while the breath technician became available.

As a result, the first breath sample was not taken until approximately 10:55 p.m., more than two hours after Mr. A had been driving. A second sample was taken shortly afterward, both readings being over the legal limit.

Mr. A was charged with impaired driving and operating a motor vehicle with a blood alcohol concentration over the legal limit. At first glance, the case appeared straightforward. However, the timeline revealed a significant delay between the time of driving and the breath testing, raising important issues about whether the legal requirements had been met and whether the Crown could rely on the breathalyzer results as conclusive proof.

What the Law Says About Timing

In impaired driving cases, timing is not just a detail. It is a key part of how the Crown proves the charge in court.

Under the Criminal Code, the Crown can rely on breathalyzer results as conclusive proof of blood alcohol concentration at the time of testing, but only if strict legal requirements are met. One of the most important requirements is timing.

To rely on this shortcut, the Crown must show:

  • The first breath sample was taken within 2 hours of driving
  • The officer made the breath demand and obtained the samples as soon as practicable
  • The testing was done properly using an approved instrument

If the first sample is taken outside the 2-hour window, the Crown cannot rely on the readings in the usual way. Instead, they must prove the person’s blood alcohol level at the time of driving through other evidence, which is often much more difficult.

Soon As Practicable

In addition, even where the test is close to the 2-hour limit, the court may still examine whether the police acted as soon as practicable.

Delays caused by investigation steps, transport, or waiting at the station may become important. In some cases, those delays raise questions about whether the legal requirements were followed.

In Mr. A’s case, the first breath sample was taken after the two-hour limit had already passed. The delay was not caused by Mr. A, but by the officer remaining at the roadside, waiting for a tow truck, transporting him to the station, and then waiting for booking and testing.

As a result, the defence focused on whether the Crown could rely on the breathalyzer readings at all. Where the timing requirements are not met, the breath test results may lose their usual strength, and this can create a real opportunity to challenge the case at trial.

What Happened at Court

When the matter proceeded to court, the Crown Attorney reviewed the disclosure and focused on the timing of the breath samples. It became clear that the first breath test had been taken outside the two-hour window required to rely on the readings as conclusive proof.

As a result, the Crown could not rely on the breathalyzer results in the usual way to prove the “over 80” charge. The case then shifted to whether there was enough evidence to proceed on the impaired driving charge.

In this case, the evidence was limited. The officer noted an odour of alcohol, but there were no clear signs of impairment such as slurred speech, unsteady balance, or poor coordination. There was no evidence of bad driving, and the interaction with police did not reveal any obvious impairment.

Without the ability to rely on the breathalyzer readings, and with no independent evidence of impairment, the Crown did not have a reasonable prospect of conviction.

As a result, the charges against Mr. A were withdrawn.

What This Means for Your Case

This case shows that a DUI charge is not decided by a number alone. Timing, procedure, and the details of the investigation can make a real difference in how the evidence is treated in court.

Many people assume that once a breathalyzer registers a reading over the limit, the case is over. However, the law requires the Crown to meet strict conditions before those results can be used as conclusive proof. If those requirements are not met, the case may depend on other evidence, which is often much weaker.

In many situations, the defence will carefully review:

  • The timing between driving and the first breath sample
  • Whether the police acted as soon as practicable
  • Delays at the roadside, during transport, or at the station
  • Whether there is any real evidence of impairment beyond alcohol consumption

These details are not technicalities. They are legal requirements that the Crown must prove beyond a reasonable doubt.

In Mr. A’s case, once the breathalyzer results could not be relied upon, there was no independent evidence of impairment. As a result, the charges could not proceed.

Every case is different. However, this example shows why it is important to have a criminal defence lawyer review the full timeline, the disclosure, and the court process before making any decisions. Where there are weaknesses in the evidence, they are often found in the details.

Speak with a DUI Lawyer Today

If you have been charged with a DUI, do not assume the case is over because of a breathalyzer result.

The timing of the demand, the delay before testing, and the full sequence of events can all affect whether the evidence can be used against you.

Before making any decisions or considering a guilty plea, it is important to have your case reviewed by an experienced criminal defence lawyer who understands DUI law and how to assess timing, disclosure, and the court process.

Call Charitsis Law at 647-930-0200 to speak directly with a criminal lawyer. Your consultation is confidential, and early advice can make a significant difference in the outcome of your case.

Breathalyzer Timing FAQs

Q. Does the breathalyzer test have to be within 2 hours of driving?

A. Yes. The law focuses on the timing of the first breath test. In most cases, the Crown must show that the first sample was taken within 2 hours of driving to rely on the result as strong proof. If the test is taken after that window, the Crown may not be able to use the reading in the usual way.

Q. What happens if my breath test was taken after 2 hours?

A. If the first test is outside the 2-hour limit, the case can change in a big way. The Crown may have to prove your blood alcohol level at the time of driving using other evidence. This is often harder to do and can create a real defence opportunity at trial.

Q. Do police have to act quickly when taking breath samples?

A. Yes. Police must act “as soon as practicable.” This means they cannot delay without a good reason. Long waits at the roadside, delays in transport, or slow processing at the station can all raise legal issues about whether the testing was done properly.

Q. Can delays in testing help my defence?

A. In many cases, yes. Delays can weaken how the breathalyzer results are used in court. If the timeline shows gaps or unnecessary waiting, the defence may argue that the legal requirements were not met. This can affect whether the evidence is reliable.

Q. What if there is no evidence of impairment besides alcohol?

A. The Crown must prove impairment beyond a reasonable doubt. If there are no signs like slurred speech, poor balance, or bad driving, the case may be weak without the breath test results. An odour of alcohol alone is usually not enough to prove impairment.

Q. Can a DUI lawyer challenge breathalyzer timing in court?

A. Yes. A DUI lawyer can review the full timeline, including the stop, arrest, transport, and testing. By examining the disclosure and the court process, they can identify delays or legal issues that may affect whether the Crown can rely on the breathalyzer results.

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Winning Case Results

Charges Dismissed – Insufficient Evidence
The Crown must prove impairment beyond a reasonable doubt. Evidence such as poor driving or alcohol consumption alone is not enough. Where the proof falls short, the court may dismiss the charges. See how it was dismissed ›››
DUI Cases Won – Reasonable Doubt
A refusal charge requires proof beyond a reasonable doubt that the accused intentionally failed to comply with a lawful demand. Where the evidence is unclear or inconsistent, the court may find reasonable doubt and dismiss the charge at trial. See how it was dismissed ›››
Time Delays – 11(b) Charter Application
Excessive delay in bringing a case to trial can violate an accused person’s Charter rights. Our DUI lawyers review timelines and disclosure to identify unreasonable delay, and in the right case, an 11(b) application can result in the charges being dismissed before trial.
See how it was dismissed ›››
Breathalyzer Calibrations & DUI Defence
Breathalyzer evidence must be reliable to support a conviction. If the device is not properly tested, maintained, or calibrated, the results may be challenged and excluded, which can significantly weaken the Crown’s case.
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DUI Defence – Reasonable Doubt
A DUI conviction requires proof beyond a reasonable doubt. Even where there is evidence of drinking or poor driving, the case may fail if the Crown cannot establish impairment to the legal standard.
See how it was dismissed ›››
Identity Issues in Care & Control Cases
In care and control cases, the Crown must prove the accused was the person in control of the vehicle. If identity is unclear or not proven, the charge cannot succeed and may be dismissed.
See how it was dismissed ›››
Identity Issues in DUI Defence
The Crown must prove the accused was the driver or had care and control of the vehicle. If identity is in doubt, the prosecution cannot succeed, and the charge may be dismissed.
See how it was dismissed ›››
Intent to Drive – DUI Defence
In care and control cases, intent is a key issue. If the accused did not intend to operate the vehicle and had a clear alternative plan, the court may find that an essential element of the offence is missing.
See how it was dismissed ›››
DUI Cases Won – Medical Defence
Medical conditions can affect how symptoms appear during a DUI investigation. Where evidence shows that impairment signs were caused by a medical issue rather than alcohol, charges may be withdrawn or dismissed. See how it was dismissed ›››

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